A.
the proteins in the host's cytoplasm.
B.
the enzymes produced by the virus before it infects the cell.
C.
the enzymes carried by the virus.
D.
whether its nucleic acid is DNA or RNA.
E.
the proteins on its surface and that of the host.

A.
They invariably kill any cell they infect.
B.
They can incorporate nucleic acids from other viruses.
C.
They must use enzymes encoded by the virus itself.
D.
Viral DNA always inserts itself into host DNA.
E.
They cannot reproduce outside of a host cell.

Which of the following statements describes the lysogenic cycle of lambda (λ) phage?

A.
The phage DNA is incorporated by crossing over into any nonspecific site on the host cell's DNA.
B.
Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic.
C.
After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses.
D.
The phage genome replicates along with the host genome.
E.
Most of the prophage genes are activated by the product of a particular prophage gene.

A.
Replication of their genomes does not involve the proofreading steps of DNA replication.
B.
RNA viruses replicate faster.
C.
RNA viruses are more sensitive to mutagens.
D.
RNA nucleotides are more unstable than DNA nucleotides.
E.
RNA viruses can incorporate a variety of nonstandard bases.

A.
Replication of their genomes does not involve the proofreading steps of DNA replication.

Most molecular biologists think that
viruses originated from fragments of cellular nucleic acid. Which of the
following observations supports this theory?

A.
Viruses contain either DNA or RNA.
B.
Viruses are enclosed in protein capsids rather than plasma membranes.
C.
Viruses can reproduce only inside host cells.
D.
Viral genomes are usually more similar to the genome of the host
cell than to the genomes of viruses that infect other cell types.
E.
Viruses can infect both prokaryotic and eukaryotic cells.

D.
Viral genomes are usually more similar to the genome of the host
cell than to the genomes of viruses that infect other cell types.

Refer to the treatments listed below to answer the following questions.

You
isolate an infectious substance that is capable of causing disease in
plants, but you do not know whether the infectious agent is a bacterium,
virus, viroid, or prion. You have four methods at your disposal that
you can use to analyze the substance in order to determine the nature of
the infectious agent.I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectiousII. filtering the substance to remove all elements smaller than what can be easily seen under a light microscopeIII. culturing the substance by itself on nutritive medium, away from any plant cellsIV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious

Which treatment could definitively determine whether or not the component is a viroid?
Student Response
Correct Answer
A.
I
B.
II
C.
III
D.
IV
E.
first II and then III

Refer to the treatments listed below to answer the following questions.

You
isolate an infectious substance that is capable of causing disease in
plants, but you do not know whether the infectious agent is a bacterium,
virus, viroid, or prion. You have four methods at your disposal that
you can use to analyze the substance in order to determine the nature of
the infectious agent.I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectiousII. filtering the substance to remove all elements smaller than what can be easily seen under a light microscopeIII. culturing the substance by itself on nutritive medium, away from any plant cellsIV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious

The difference between vertical and horizontal transmission of plant viruses is that

A.
vertical transmission is the transfer of DNA from a plant of one
species to a plant of a different species, and horizontal transmission
is the spread of viruses among plants of the same species.
B.
vertical transmission is the spread of viruses from trees and tall
plants to bushes and other smaller plants, and horizontal transmission
is the spread of viruses among plants of similar size.
C.
vertical transmission is the transfer of DNA from one type of plant
virus to another, and horizontal transmission is the exchange of DNA
between two plant viruses of the same type.
D.
vertical transmission is the spread of viruses from upper leaves to
lower leaves of the plant, and horizontal transmission is the spread of a
virus among leaves at the same general level.
E.
vertical transmission is transmission of a virus from a parent plant
to its progeny, and horizontal transmission is one plant spreading the
virus to another plant.

E.
vertical transmission is transmission of a virus from a parent plant
to its progeny, and horizontal transmission is one plant spreading the
virus to another plant.

A microbiologist analyzes chemicals obtained from an enveloped RNA virus that infects monkeys. He finds that the viral envelope contains a protein characteristic of monkey cells. Which of the following is the most likely explanation? ( Concept 19.1)